Biology Lessons
by RiiiiiChan
Summary: Krista finally gets the confidence to ask her crush to help her for the upcoming Biology test this week. Though they get stuck when it comes to a certain subject during their lesson. Krista/Armin one-shot High School AU Lemon. [Requested]


**Author's Note: **Hello there, if you follow me, I'm so sorry but my friend requested this fic. And I felt that I should do something being that I haven't uploaded or updated in a while, so here's a one shot high school AU lemon for Krista and Armin! Enjoy if you can because I really rushed this, sorry. :)

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The bell rang, which only meant the school day was over. The blonde girl hurried past moving students to another person of her age, a male with golden locks, Armin.

"Armin," The blonde tapped his shoulder gently, whilst the golden haired boy was cramming his books into his bag. Armin turned around, it felt like the world was in a slow motion for a good second as his beautiful golden strands of hair swayed in his motion of turning around. Her knees got weak.

_When did she begin to like his looks so much?_

"Yes, Krista?" He grinned, his pearly whites flashing her. His eyes scrunched slightly, oh how those crystal blue pupils glittered. How beautiful they were, that both of them had lay sight on her figure.

Krista gulped nervously, her throat felt like it was on fire.

"Armin," Her cheeks began to change colors from apricot to pink, "Would you mind tutoring me in Biology today? I really need help in this certain subject and -"

"Sure, of course." He answered with a nod, stunning her.

**_HE SAID YES SO QUICKLY. _**

Krista felt herself leaning back, feeling accomplished, her cheeks turned into a brighter shade of pink. While staring into his eyes, feeling the giddiness of his acceptance, the blonde girl didn't realize she was still leaning back into the empty space behind her. She gasped, realizing it was too late to find support and closed her eyes, waiting for her back to hit the cold, marble tiled floor of the Biology lab.

"Krista, are you okay?" A concerned, soft voice asked. It was Armin's and she realized it sounded very close. Her eyes opened, his nose and her nose were just an inch apart while his arms held her petite figure close to his body. The sensation of his bare skin touching her's made her chest burn, and along the realization of him being so close to her **_ever_ **made her want to scream to the heavens.

"Krista," His voice grew more concerned, "Are you getting a fever? Your face is very red..." His palm slid under the long, uneven fair fringe on her forehead. The contact of skins made her cheeks turn brighter!  
"You're kind of warm..."  
She pulled away from his hold and nodded, "Don't worry I'm fine!"  
Armin looked at her once, curiously, then smiled.

"Alright then, so shall we head on over to the library or would it just be easier if you came over to my place?"

The question dazed her. _Did he just offer her to come to his place?!_

She hesitated, "Uh... okay, we'll go to your place." Her insides squirmed. She was nervous and happy at the same time.

Armin nodded and pulled the handle of his shoulder bag onto him, "Let's go, then."

_**x - x - x - x**_

The pair of blondes arrived within Armin's apartment complex. It took a 20 minute walk from school to his street exact.

Armin lived in the damaged, unsafe part of town. She was slightly appalled as she walked down the street to his building. Unlike Armin, Krista came from a wealthy family and lived in a posh, quiet street. Armin, however, was **very** different. Armin grew up with his parents and grandfather in a small house when he was younger, but his parents died in a tragic car accident and soon after, his grandfather passed away. Leaving him by himself. With no one to help him, Armin managed to somehow get an apartment in a building that he was working for as a janitor.

Krista had asked him before and he told his story. Her heart shattered to hear of his gloomy past. She only wished his future would get better...

The golden haired boy welcomed Krista into his abode. A long, white hallway led to the living room, which had three entrances. One for the bathroom, one leading to the kitchen, and Armin's room.

"Do you want to study here?"

"Uh..." She hesitated, her heart beating wildly. She couldn't believe she was actually in his apartment! "Sure!"

"Alright," The golden haired boy walked over to the old couch in the small living room and placed his bag at the corner. He turned to the fair haired girl standing awkwardly, staring at him.

"Would you like anything to drink? Tea, water?"

"W-water would be nice!" She stuttered as her voice cracked. She blushed and Armin chuckled softly under his breath. The golden haired boy left to the kitchen.

Krista stood for another second or so and slowly walked to the couch, cautiously taking a seat at the edge. Her short navy blue school skirt was beginning to ride up, she panicked trying to pull it down. Armin walked back into the living room with a glass of water and a few alterations to his school uniform. His tie was hanging loosely from his neck, and his white button down shirt was slightly unbuttoned, showing his collarbone. The sleeves of his shirt were rolled up to his elbows.

Krista took the water and drank it nervously, trying not to be totally mesmerized by his whole _messy look. _Armin opened his bag and removed a big Biology textbook as Krista finished chugging down the water. She placed it on the floor beside her foot.

"Okay," Armin plopped down next to her, she bounced up with his sudden weight on the couch, and found herself sitting right next to him. Lap touching lap. She blushed harder, but she had to focus... she was here to study after all!

"So what do you need help understanding?"

"Well, since our Biology test this week is going to be about the human body, let's review that."

"Alright then." Armin flipped open the textbook and reached at a page that would begin their study session...

**_x - x - x - x_**

Two hours passed, it was now 5:30. Krista, by now, was able to speak fluently to Armin with an occasional stutter. But she was actually studying! She was beginning to understand the function of chemicals in the body as well as the organ systems, and much more. It was all thanks to Armin, of course. A few times during the session, Krista would blankly observe Armin. He has so much passion fizzing up inside of him whenever he was explaining something. He enjoyed learning, his eyes twinkled every time he got to fully understand something. Krista deeply admired him for his passion in learning new things, if she had to confess why she even had a crush on him, it was mainly because of this. The passion in his eyes brought life and warmth to her, and she couldn't help but smile every time his eyes twinkled.

"Okay, let's see what's next..." Krista confidently turned the page of the textbook only to find words that made her heart stop. Even Armin paused, unsure of whether to continue or not.

"**Sexual Reproduction and It's Organs**" were written at the top of the page, and pictures of male and female reproductive organ drawings were shown.

"Um..." Armin swallowed uncomfortably, his hand pointed at a word in the starting sentence. Krista could tell he was trying to read it in front of her, she also noticed he was blushing! Armin swallowed again and before he could try, Krista placed her palm upon his hand.

"It's okay, Armin. You don't have to help me with this part..." She grinned at him, graciously.

Armin's brows furrowed, "What? But that won't be right... you'll fail the test if you don't know this."

"Oh yeah?" Krista raised a brow prissily, "how do you know I don't know this?"

Armin instantaneously began blushing, "Well... then... prove to me how much you know about this part of the subject." He demanded shyly. Krista slumped nervously, thinking of things to say and then... a bold idea stretched her mind.

"Would you mind me showing you?" The words slipped off her tongue shyly, but Armin quickly understood what she meant. He jerked back in surprise, now blushing a darker shade. The textbook tell onto the floor from his lap.

"Like...as in... '_show me_' show me? As in... giving a _physical_ presentation?!" He blinked confusedly, noticing how beautiful her eyes always were even now, as she gave him an innocently-seductive look. The fair haired girl nodded, stretching her neck to him.

Krista closed her eyes and waited. Her moist lips poised, waiting for his.

"Armin..." She whispered, "I like you a lot." The words caused for his heart to stop.

Little did she know, but he longed to hear those words. He bent forward until their lips finally met. It was like a hurricane of adrenaline rushed throught their veins when their lips collided. Their bodies shifted onto the couch as they kissed. Krista kicked off her shoes as she pushed herself onto Armin's body, topping him between his legs.

They continued kissing. His hands began getting frisky, as they were squeezing her waist. He pulled from her mouth for a breath, "Would you teach me about your body?" He teased with a smirk, his hands grabbed her bum.

She squeaked.

"If you do the same." She teased back and smashed her lips back on his. Armin chuckled as her lips constantly moved against his.

He pulled her tucked shirt from her skirt and began unbuttoning them. She broke the kiss and helped him undress her. Her shirt first came off, then her skirt. She was now concealed only in her pink bra and panties and navy blue thigh high socks. They began kissing once again, his hand reaching from behind her back, unhooking her bra. The fair haired girl tossed it to the side, her breasts were now free of the bras grip and slumped with gravity. She blushed, but he grabbed onto her breast and groped her bum, pulling her to him again. Again, kissing resumed, and now her hands were getting fidgety.

He helped her unbuckle his pants and unbutton his shirt. Those articles of clothing were tossed aside, except for his red tie which hung from his neck. All he had left were his boxers and she, her panties and socks.

The golden haired boy then removed his boxers. His member stood erect. Krista admired Armin's nude self for a good moment. She could feel the material of her panty beginning to soak as she admired every inch of his pale body. He was skinny but he had muscle showing and his member was _very_ lengthy, much more than she had expected...

She sat back, spreading her legs apart and removed her panties from her body, which were tossed to the ground. With her legs wide open, Armin stroked his member, observing Krista's exposed pink slit. He bit his lip moaning.

"Stay there," He commanded her, as he made his way between her legs and pushed her down on her back. He spread her legs wider and began kissing her neck. His member's head was rubbing against her cave. The sensation of it drove her insane.

"Armin..." She moaned, digging her nails into his back.

From her neck, he reached her breast. He took one nipple in his mouth and continuously flicked it with his tongue, playfully. She gasped, his member's head was still rubbing against her cave.

"Armin.. fuck me. Fuck me hard, do it please." She begged, her legs closing as she was getting impatient.

He began kissing lower, and spread her legs apart again. His head made it between her legs, he sat up straight, now looking down at her cave. His finger stroked her clit once, she reacted in a loud moan. He once again stroked it, another moan. Then he began rubbing it, which made her groan with pleasure.

"Armin... please... Armin..." She bit down on her lip.

He pulled his hand back, and straddled her. His hands clutched her knees. Without hesitation, he pushed in all the way, groaning. She yelped. Her cave was tight, but he pushed deeper until he managed stay put. He leaned into her, still holding her knees.

"Krista, you're very... _snug_." He grunted with a smile. She bit down on her lip and moaned, pushing her hips at him to continue.

He grit his teeth and began thrusting into her. Both of their names were being yelled out as his hips slammed at her. The fair haired girl's hips gyrated with the many fast and powerful thrusts he gave her.

Some time passed, he was still going strong.

"A-Armin..." She moaned his name, scratching down his back.

More time passed, still thrusting and panting escaped his lips.

"Krista... ah, god, you're so tight." He moaned, kissing her neck.

His panting was beginning to slow down and with one last mighty thrust, he yelled her name in lovely ecstasy, and exploded his liquids into her. She leaned her head back and gave a loud moan, feeling herself climax as well.

Still attached, she sat up straight on his lap, wrapping her legs around his waist. Her panting was heavy.

"Was I a good teacher?" She grinned, he nodded and placed his lips on her's.

_**x - x - x - x**_

The final bell of the day rang. Krista quickly made it to Armin's table, where he sat with Mikasa and Eren.

"Armin, guess what I got on the test!"

"What did you get?" He smiled eagerly, hoping to hear the answer of 100.

"A score of 78! But that's only because I failed _that part_ of the test, but we should _study_ sometime again soon." She winked at him. Though shocked she didn't get a 100, he grinned knowing what she meant.

"Well of course. How about we _study_ sometime again today?" He winked back.

"Sure thing. See you after school." The fair haired girl smiled one last time and walked out of the Biology lab room.

"'_Study_?'" Mikasa and Eren both looked confusedly at the boy with golden hair, who only shrugged and replied, "Study."

* * *

**The End**


End file.
